Two experiments related to the development of verbal self-control in children were conducted. In the first experiment, 36 adults and 36 four year olds were administered a vocal alone, a motor alone, and a combined-reaction-time task. In the second experiment, 54 kindergarten subjects and 60 fifth-grade subjects were each administered a double motor (a motor response followed by a second motor response), a double vocal ("Go,""Go"), and a combined vocal-motor reaction-time task. The results indicated that when two overt responses are combined, the initial response is somewhat inhibited, but that there is nothing unique about the vocal response in this process: the latency of the initial response was the same whether it was followed by a vocalization or by a second motor response. Further, by the age of four, there was no difference between the ability to combine two motor responses and the ability to combine a motor response and a vocal response. (Author/AA)